Warfare And Altruism: Flip Sides Of The Same Human Instinct?"Other animals fight over limited resources and desirable mates, but humans fight for both biological and cultural reasons. We alone will go to war to defend our honour and values. ... What's more, conflict seems to be an integral part of our social organisation. ... Paradoxically, these antagonistic tendencies may be intimately linked with another, much more noble side of human nature: our unparalleled capacity for large-scale cooperation and altruistic self-sacrifice."
New Scientist 09/25/12